Form melds, knock strategically, and play to 100 against AI
Gin Rummy is a classic two-player card game where the goal is to form melds — sets of three or four cards of the same rank, or runs of three or more consecutive cards of the same suit. Players draw and discard cards each turn, trying to reduce their "deadwood" (unmatched cards) to knock or go Gin. Gin Rummy was invented in 1909 and became hugely popular in Hollywood, with stars like the Marx Brothers playing between takes.
Each hand, 10 cards are dealt to both players. On your turn, draw from the stock or discard pile, then discard one card. Arrange your hand into melds to lower your deadwood count. When your deadwood is 10 or less, you can knock. If you have zero deadwood, declare Gin for a 25-point bonus. The first player to 100 points wins the match. Be careful though — if your opponent has lower deadwood when you knock, they score an undercut bonus instead!
Knock when your deadwood is low (under 5 points) and you suspect your opponent has high deadwood. Going for Gin is riskier but more rewarding — you earn a 25-point bonus and your opponent cannot lay off cards. If your deadwood is close to 0, it's often worth trying for Gin, especially early in a hand before your opponent has time to organize their melds.
When you knock, your opponent reveals their hand and lays off any cards that extend your melds. You score the difference between your opponent's remaining deadwood and yours. Going Gin earns the opponent's full deadwood plus a 25-point bonus. Getting undercut means your opponent scores the difference plus a 25-point undercut bonus.
An undercut occurs when you knock and your opponent ends up with equal or lower deadwood than you (after laying off cards on your melds). Instead of you scoring, your opponent gets 25 bonus points plus the deadwood difference. This mechanic rewards defensive play and makes it risky to knock with high deadwood.